Pump-and-motor unit, particularly for supplying fuel

ABSTRACT

A pump-and-motor unit comprises, within a sealed housing, a lateral channel pump and an electromotor, the rotor of which drives the impeller of the pump. The unit housing has at each end an axially aligned liquid inlet and outlet nipple, respectively. At the pressure side of the pump the liquid is guided from the lateral channel of the pump radially inwardly through a pressure channel provided in a lateral channel plate serving as a pump housing.

1 1 Swim l Botteher et a1.

tent 1 PUMP-AND-MOTOR UNIT, PARTICULARLY F 01R SUPPLYHNG FUEL [75]Inventors: Siegfried Bottcher, Aldingen;

Hans-Reimer Speck, Stuttgart, both of Germany [73] Assignee: RobertBosch Gmblll, Stuttgart.

Germany [22] Filed: Nov. 28, 1972 [21] Appl. No.1 310,115

[30] Foreign Application Priority Data Nov. 29, 1971 Germany 2159025[52] US. Cl. 417/423, 415/213 T, 415/53 T [51] int. C1. F04b 17/110 [58]lField of Search 417/423; 415/53 T, 213 T [56] References Cited UNITEDSTATES PATENTS Fabig 415/53 T [451 Sept. 17, 119% 2,817,296 12/1957Fabig 415/53 T 3,418,991 12/1968 Schultz et a1. 417/423 R 3,658,4444/1972 Rhodes et a1. 417/423 R Primary Eraminer-C. J. Husar Attorney,Agent, or Firm-Edwin E. Greigg 5 7 ABSTRACT A pump-and-motor unitcomprises, within a sealed housing, a lateral channel pump and anelectromotor, the rotor of which drives the impeller of the pump. Theunit housing has at each end an axially aligned liquid inlet and outletnipple, respectively. At the pressure side of the pump the liquid isguided from the lateral channel of the pump radially inwardly through apressure channel provided in a lateral channel plate serving as a pumphousing.

11 Claims, 2 Drawing Figures mgmmsw mm 39886.29];

sum 1 [1F 2 Fig.1

PUMP-AND-MOTOR UNIT, PARTICULARLY FUR sUlPlPLYllNG lFlUlEL Thisinvention relates to a pump-and-motor unit which is particularly adaptedfor supplying fuel and which comprises a lateral channel pump and anelectromotor. The liquid, as it flows through the unit, cools thearmature assembly of the electromotor by contact and lubricates thebearings of the rotary components.

In pump-and-motor units of the aforenoted type it is of primaryimportance that the length and the diameter of the pump component be assmall as possible. The degree of efficiency of these pumps is of lesserimportance since delivery takes place under low pressure, the deliveredquantities far exceed the quantities actually needed and the pressure ismaintained substantially at a constant level by means of an overflowvalve.

In a known pump-and-motor unit of the above type (such as disclosed inGerman Published Patent Application DOS 1,703,784) the suction andpressure conduits of the pump terminate axially in the lateral channeland are oriented in the same axial direction. In more recent designs ithas been sought to attach the fuel inlet and outlet conduits at eachaxial end of the pump-and-motor unit. In this manner, as far asstructure is concerned, the pump-and-motor unit has the outer appearanceof an enlarged portion of the fuel line ,so that, for example, itsorientation in mounting does not have to be changed. If one were toestablish this type of fuel path in the known pump-and-motor unit, thena channel should be provided about the impeller externally thereof. Sucha solution, however, would lead to an undesirable increase of theoverall diameter of the pump-and-motor unit.

It is an object of the invention to provide an improved pump-and-motorunit of the aforenoted type in which the admission and withdrawal offuel is effected at the two axial ends of the pump and in which thedimensions, particularly the diameter of the pump, is maintained at asmall value, while consideration is given to the requirement that thehigh and low pressure sides of the pump have to communicate with oneanother through the aforenoted overflow valve.

Briefly stated, according to the invention, the removal of fuel throughthe unit is effected through a pressure channel from the lateral channelradially with respect to the rotary axis of the pump rotor.

The invention will be better understood, as well as further objects andadvantages will become more apparent, from the ensuing detailedspecification of a preferred, although exemplary, embodiment taken inconjunction with the drawing, wherein:

FIG. 1 is a longitudinal sectional view of a pump-andmotor unit takenalong line I-l of FIG. 2 and FIG. 2 is a sectional view of thepump-and-motor unit taken along line II-Il of FIG. l.

The pump-and-motor unit which is of compact structural design, comprisesa liquid delivery pump 1 and an electromotor 2 which are enclosed in atwo-part housing 3, 4. The liquid, such as fuel, flows in the directionof the axial arrows and first passes through the delivery pump ll.Thereafter the liquid flows longitudinally through the housing 3, 4through the electromotor 2. In the housing portion 3, which comprises aninlet nipple 5, there is disposed a lateral channel plate 6 centered bymeans of a sealing ring 7 and rigidly connected with a fixed shaft 3. Onthe latter there is rotatably mounted a rotary assembly generallyindicated at 9 which comprises the rotary components of the electromotorand an impeller of the lateral channel pump. The rotary components ofthe electromotor 2 comprise, essentially, an armature formed of awinding 111 and of armature plates l2, a radial collector l3, bearingsM, as well as a casing 15 which is made of synthetic material and whichencloses the armature. The casing 15 and the impeller 10 are made of thesame material and are preferably manufactured as a one-piece component.The structural connection between the im' peller l0 and the motorarmature is effected by radially arranged webs Illa.

In the cylindrical housing portion 3 there is inserted a tubular housing17 supported by the lateral channel plate '6. The housing 117 containscircumferentially spaced permanent magnets 13. The latter are axiallyoffset with respect to the armature of the electromotor to cause thearmature to be biased in the direction of the lateral channel plate 6.The bearing 14 provided in the zone of the impeller 10 thus serves notonly as a radial bearing but also as a thrust bearing abutting thelateral channel plate 6. The clearance between the impeller l0 and thelateral channel plate 6 is determined by the length by which the bearing14 projects axially beyond the casing 15 towards the plate 6. Thisclearance, through which the liquid may flow to the bearings 14 tolubricate the same, is thus maintained at a constant width duringoperation by virtue of the axially biased rotary assembly 9.

The housing portion 4 fits into the housing portion 3 in a plug-likemanner and closes the same fluid tight by virtue of an inserted O-ring19. In the housing portion 4 there are situated carbon brushes 20 whichare urged against the radial collector 13 by springs 21. In addition,the housing portion 4 includes the outlet nipple 22. A support ring 23fixedly held in the housing portion 4 serves as a further support forthe shaft 8 in addition to the lateral channel plate 6.

As it may be observed in FIGS. 1 and 2, the liquid, such as fuel, isadmitted through the inlet nipple 5 and an inlet opening 25 provided inthe lateral channel plate 6 into the lateral channel 26. After flowingthrough the latter, the liquid is, at the pressure side of the pump 1,admitted through a pressure opening 27 arranged radially with respect tothe axis of rotation to an annular groove 23 provided in the lateralchannel plate 6. From the pressure opening 27 there extends, within theplate 6, an axial channel 29 which leads to the suction side of thepump-and-motor unit and is controlled by means of an overflow valve 30.The latter comprises a plate 311 which is tiltable about one end 32which, in turn, is supported by a radial face of the lateral channelplate 6. The plate 3i has an orifice 33 through which passes the shaft3. The plate 3i is loaded by a spring 34, which at its other end engagesa ring 35. The latter frictionally engages the shaft 3. but is axiallydisplaceable thereon for the purpose of varying the opening pressure ofthe valve 30.

In that portion of the lateral channel plate 6 which serves forseparating the suction side 25 of the pump ll from the pressure side 27thereof and in that face of the plate 6 which is oriented towards theimpeller 110, there is provided after the downstream end of the lateralchannel 26 a cavity 37 which is at the same distance from the pump axisas the channel 29 and which leads through a radial channel 38 to theannular groove 28. In this manner, the pressure drop between the suctionside 25 and the pressure side 27 is substantially reduced: the portion39 of the lateral channel is dis-- charged and thus a depressurizationis effected. The portion 39 joins the lateral channel 26 and extends asa continuation of the lateral channel 26 with approximately the halfwidth thereof and ends spaced from the cavity 37. In the extension 39 ofthe lateral channel 26 there prevails a certain overpressure of theliquid which has a rearward effect on the lateral channel 26 andcounteracts the vaporization of the volatile liquid, such as fuel.

From the annular groove 28 of the lateral channel plate 6 the liquid isadmitted into an annular groove 40 of the rotary assembly 9. The groove40 communicates with the motor chamber 42 through channels 41. It isthus seen that the liquid first flows radially inwardly in the lateralchannel pump and is then guided axially and centrally into the motorchamber 42. This has the advantage that the diameter of the impeller 10may be increased causing a higher peripheral speed of the liquid in thelateral channel 26. This results in a better pressure head at lower rpmsand thus in a greater life expectancy of the pump.

The webs 10a bound the channels 41 between the impeller l0 and thecasing and operate as a centrifugal pump aiding the flow of liquid. inthis manner the lateral channel pump 1 is relieved at the pressure side.This relief, however, is maintained at such a low level that on thepressure side of the lateral channel pump no vaporization of the fueloccurs and there prevails a sufficient resistance for maintaining thesupply pressure of the lateral channel pump constant.

What is claimed is:

1. In a pump-and-motor unit for driving liquid, said unit being of theknown type that has (a) a sealed housing defining a motor chamber, (b) aliquid inlet means and a liquid outlet means passing through saidhousing, (0) an electromotor disposed in said motor chamber andincluding an armature, (d) means, including bearing means, for rotatablysupporting said rotary components of said electromotor, (e) a lateralchannel pump disposed in said housing and having means defining alateral channel, (f) an impeller forming part of said lateral channelpump and driven by said electromotor, the improvement comprising apressure channel formed in said lateral channel defining means andextending inwardly from said lateral channel in a radial direction withrespect to the rotary axis of said impeller, said liquid being driveninto said lateral channel and from said lateral channel through saidradially extending pressure channel toward said motor chamber.

2. An improvement as defined in claim 1, said impeller and said armatureforming a unitary rotary assembly including channel means for guidingthe liquid within said motor chamber, said last-named channel meansterminating on the lateral surface of said armature.

3. An improvement as defined in claim 2, wherein said impeller beingaffixed to said armature by a plurality of radially extending laminarwebs bounding said channel means, whereby said webs acting as vanesdrawing liquid from said lateral channel pump and delivering it intosaid motor chamber.

4. An improvement as defined in claim 1, wherein said lateral channeldefining means comprises a lateral,

channel plate containing said lateral channel, an annular grooveprovided in said lateral channel plate and arranged concentrically withrespect to the rotary axis of said impeller, said radial pressurechannel merging into said annular groove.

5. An improvement as defined in claim 4, said impeller and said armatureforming a unitary rotary assembly adapted to be axially displaced, saidrotary assembly including an additional annular groove facing theannular groove provided in said lateral channel plate, channel meansprovided in said rotary assembly for guiding the liquid within saidmotor chamber, said last-named channel means extending from saidadditional annular groove and terminating on the lateral surface of saidarmature.

6. An improvement as defined in claim 5, including a radial air gapdefined between said lateral channel plate and said impeller, both saidannular grooves being in communication with said radial air gap.

7. An improvement as defined in claim 6, said electromotor includingstationary magnets disposed in said motor chamber spaced from saidarmature and offset with respect thereto in the direction of saidlateral channel pump for biasing said impeller in the direction of saidlateral channel plate.

8. An improvement as defined in claim 2, including a fixed shaftextending within said housing, said rotary assembly including an axialbore through which said fixed shaft passes.

9. An improvement as defined in claim 8, including A. a valve channelprovided in said lateral channel pump for connecting the pressure sideof said lateral channel pump with the suction side thereof,

B. a valve plate movably supported on said shaft adjacent that side ofsaid lateral channel plate that is remote from said rotary assembly,said valve plate controlling said valve channel,

C. a spring surrounding said shaft and engaging said valve plate and D.an axially adjustable spring support means attached to said shaft andengaged by said spring.

10. An improvement as defined in claim 1, including A. a unitary rotaryassembly formed of said impeller and said armature,

B. a lateral channel plate comprising said lateral channel definingmeans, said plate being disposed axially spaced from said unitary rotaryassembly, said lateral channel being provided on that face of saidlateral channel plate that is oriented towards said unitary rotaryassembly and C. a cavity provided on said face of said lateral channelplate and being spaced downstream of said lateral channel and disposedat the same distance from the rotary axis of said impeller as saidlateral channel, said cavity communicating with said radial pressurechannel.

11. An improvement as defined in claim 10, including a channel portionprovided in said face of said lateral channel plate, said channelportion constituting a downstream continuation of said lateral channel,said channel portion passing by said cavity at a distance therefrom andhaving a width smaller than that of said lateral channel.

1. In a pump-and-motor unit for driving liquid, said unit being of theknown type that has (a) a sealed housing defining a motor chamber, (b) aliquid inlet means and a liquid outlet means passing through saidhousing, (c) an electromotor disposed in said motor chamber andincluding an armature, (d) means, including bearing means, for rotatablysupporting said rotary components of said electromotor, (e) a lateralchannel pump disposed in said housing and having means defining alateral channel, (f) an impeller forming part of said lateral channelpump and driven by said electromotor, the improvement comprising apressure channel formed in said lateral channel defining means andextending inwardly from said lateral channel in a radial direction withrespect to the rotary axis of said impeller, said liquid being driveninto said lateral channel and from said lateral channel through saidradially extending pressure channel toward said motor chamber.
 2. Animprovement as defined in claim 1, said impeller and said armatureforming a unitary rotary assembly including channel means for guidingthe liquid within said motor chamber, said last-named channel meansterminating on the lateral surface of said armature.
 3. An improvementas defined in claim 2, wherein said impeller being affixed to saidarmature by a plurality of radially extending laminar webs bounding saidchannel means, whereby said webs acting as vanes drawing liquid fromsaid lateral channel pump and delivering it into said motor chamber. 4.An improvement as defined in claim 1, wherein said lateral channeldefining means comprises a lateral channel plate containing said lateralchannel, an annular groove provided in said lateral channel plate andarranged concentrically with respect to the rotary axis of saidimpeller, said radial pressure channel merging into said annular groove.5. An improvement as defined in claim 4, said impeller and said armatureforming a unitary rotary assembly adapted to be axially displaced, saidrotary assembly including an additional annular groove facing theannular groove provided in said lateral channel plate, channel meansprovided in said rotary assembly for guiding the liquid within saidmotor chamber, said last-named channel means extending from saidadditional annUlar groove and terminating on the lateral surface of saidarmature.
 6. An improvement as defined in claim 5, including a radialair gap defined between said lateral channel plate and said impeller,both said annular grooves being in communication with said radial airgap.
 7. An improvement as defined in claim 6, said electromotorincluding stationary magnets disposed in said motor chamber spaced fromsaid armature and offset with respect thereto in the direction of saidlateral channel pump for biasing said impeller in the direction of saidlateral channel plate.
 8. An improvement as defined in claim 2,including a fixed shaft extending within said housing, said rotaryassembly including an axial bore through which said fixed shaft passes.9. An improvement as defined in claim 8, including A. a valve channelprovided in said lateral channel pump for connecting the pressure sideof said lateral channel pump with the suction side thereof, B. a valveplate movably supported on said shaft adjacent that side of said lateralchannel plate that is remote from said rotary assembly, said valve platecontrolling said valve channel, C. a spring surrounding said shaft andengaging said valve plate and D. an axially adjustable spring supportmeans attached to said shaft and engaged by said spring.
 10. Animprovement as defined in claim 1, including A. a unitary rotaryassembly formed of said impeller and said armature, B. a lateral channelplate comprising said lateral channel defining means, said plate beingdisposed axially spaced from said unitary rotary assembly, said lateralchannel being provided on that face of said lateral channel plate thatis oriented towards said unitary rotary assembly and C. a cavityprovided on said face of said lateral channel plate and being spaceddownstream of said lateral channel and disposed at the same distancefrom the rotary axis of said impeller as said lateral channel, saidcavity communicating with said radial pressure channel.
 11. Animprovement as defined in claim 10, including a channel portion providedin said face of said lateral channel plate, said channel portionconstituting a downstream continuation of said lateral channel, saidchannel portion passing by said cavity at a distance therefrom andhaving a width smaller than that of said lateral channel.